Surface grinding machine



Jan. 13, 1942. r 'H. S ILVEN- 2,269,697 I SURFACE GRINDING MACHINE Filed Oct. l8, 1940 3 Sheets-Sheet 1 HERBERT A. 5'11. vsrv Jan. 13, 1942. v H. A; SILVEN 2,269,597

' SURFACE GRINbING MACHINE:

' Filed Oct. 18, 1 940 5 Sheets-Sheet 2 HERBERT A. 51L VEN Jan. 13, 1942; FLA. SIM/EN. 2,269,697

SURFACE GRINDING MACHINE File d Oct. '18, 1940 .3 Sheets-Sheet 3 'm I W HERBER T A. 51L. VEN

' Muwm Patented Jan. -13, 1942 SURFACE GRINDING MACHINE v Herbert A. Silven, Worcester, Mass, assignor to Norton Company, Worcester,

tion of Massachusetts Application October-18,1940, Serial No. 361,759

4 Claims.

The invention relates to grinding machines, and more particularly to' a surface. grinding machine for grinding plane surfaces on a work piece.

' One object of the invention is to provide a simple and thoroughly practical improved surface grinding machine. Another object of the invention is to provide an improved hydraulically operated grinding machine in which the work table is reciprocated longitudinally by a hydraulically operated mechanism and the wheel slide is indexed or'traversed transversely by a hydraulically operated mechanism which is controlled by and in timed relation with the table reciprocating movement.

A further object of the invention is to provide a hydraulic'wheel slide actuating mechanism in which aconstant pressure is maintained on the active end of the wheel slide cylinder and the feeding movement is obtained by metering a controlled adjustable but predetermined quantity of fluid from the other end of the wheel slide cylinder to produce a controlled, positive and predetermined transverse indexing or feeding movement of the wheel slide and grinding wheel. Other objects will be in part obvious or in part pointed out hereinafter. I

- The :invention accordingly consists in thefeatures of construction, combinations of elements,

and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims- In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of the invention,

, Fig. 1 is a front elevation of theimproved, surface grinding machine;

Fig. 2 is a diagrammatic view showing the hy- Mass., at corporaposition the periphery of-the grinding wheel |2 relative to the surface of the work piece which is mounted on the table so as to grind the surface thereof to they required extent. This feeding mechanism may comprise a manually operable feed wheel which is preferably of a type similar to the well known feeding mechanism, such as that shown in the prior U. S. pat-. ent to Norton, No. 1,108,779, dated August 25, 1914, and the U. S. patentto Flygare and Wood, No. 2,022,542, dated November 26, 1935. The manually operable feed wheel I6 is connected to rotate a gear I! meshing with a gear I8. The

gear I8 is formed with 'an internal threaded v aperture which engages or meshes with a feed screw IS, the lower end of which is fixedly mounted on the vertical slide It. It will be readily aptable II.

parent from the foregoing disclosure that rotation of the manually operable feed wheel IE will ,be imparted to raise or lower thevertical slide l4 together with the wheel slide l3 and, the

relative to the surface of the grinding wheel l2 A hydraulically operated mechanism. is provided for reciprocating the table II to recipro-,

- cate the workpiece to be ground beneath the draulicallyoperated control system and actuat ing parts; and

Fig. 3 is a fragmentary vertical sectional view,

on an enlarged scale, through the table reciprocatingmechanism.

A surface grinding machine has been illustrated in the drawings comprising a base l0 having a longitudinally movable work table II supportedon the usual V-way 8 and flat way 9 on the base III. A grinding wheel I2 is rotatably mounted on a transversely movable wheel slide l3 which is supported on. a vertically movable slide I carried by an upwardly extending portion or column l5 .of the base Ill. The vertical slide l4 is arrang ed for manual adjustment to 65 operative face-ofthegrinding wheel I2. In the preferred form, the reciprocating mechanism may comprise a cylinder 2| which is fixedly mounted within the'base ID of the machine. A piston 22 is slidably mounted within the cylinder 2| and is connected to one end of a piston rod 23. The other end of the piston rod 23 is connected to -a bracket 24 depending from the under side of the table II. The base ||l is provided with a reservoir 25 from which fiuid is pumped through a pipe 26 by means of a motor driven fluid pump 21. The pump 21 forces fiuid underpressure through a'pipe 28 to acontrol or reversing valve 29.

Fluid under pressure from the pipe 28 enters a central chamber 30 in the valve rotor 3| and in the position shown in Fig. 2, passes out through v a passage 12, a pipe 33, into the cylinder chamber 34 to move the piston 22 toward the right (Figs.

1 and 2) to transmit a corresponding movement toward the right to the table II. During this movement of the piston, fluid withinv a cylinder chamber '25 exhausts through a passage 38. through a valve chamber 31 formed in the valve rotor 3|, through a passage-38, through a throttie or speed-control valve 39 and a pipe 40, into the reservoir 25. A manuallyoperable lever 4| is provided on the front of the machine base for controlling the speed control or throttle valve 39. By manipulation of the lever 4|, the reciprocatory speed of the table II may be varied as desired or if the valve 39 is completely closed, the table reciprocation maybe stopped. A pressure relief valve 42 is connected to the pipe 28 by means of which excess fluid under presure within the system may be'by-passed directly to the reservoir 25.

A reversing lever 45 is provided for either manually or automatically shifting the rotor 3| of the reversing valve 29. The reversing lever 45 is provided with a rearwardly projecting stud 46 which is arranged in the path of a pair of adjustable table dogs 41 and 48. The table dogs 41 and 48 are adjustably mounted in the usual manner in a T-shaped groove formed on the front edge of the table II. The reversing lever 45 is rotatably supported on a stud 49 which is fixedly mounted relative to the base I 0. The reversing lever 45 is provided with an integral, downwardly extending gear segment 50 which meshes with a gear segment 5|. The gear segment 5| is mounted on the front end of a rotatable shaft 52.

A larger gear segment 53 is fixedly mounted on the inner end of the shaft 52 and meshes with a gear 54 which is fixedly mounted relative to the rotor 3| of the'reversing valve 29. The Valve rotor 3| may be manually reversed by manually shifting the reversing lever 45 from the full line position 45 (Fig. 1) intothe dotted line position 45a, (Fig. 2).

In order that the reversing valve rotor 3| may be shifted rapidly into a reverse position after the lever 45 moves toward a central position, a suitable load and flre mechanism is provided including a pivotally mounted lever 55 which is pivotally suppQrted on a stud 56 which is fixed relative to the base I I]. The upper end of the lever 55 is formed as a yoke-shaped member 51 which straddles a stud 58 which is fixedly mounted on a downwardly extending portion of the gear segment member 53. A tension spring 59 is connected at one end to a stud 60 which is fixedly mounted at the lower end of the lever 55. The upper end of the spring 59 is connected to a stud 6| carried by the gear segment member 53. It will be readily apparent from the foregoing disclosure that when the reversing lever is moved from one extreme position to the other, the

swinging movement of the lever 55 to a central position increases the tension of the spring 59 ,of the table stroke so-as to present the wheel face to a different portion of the work on each successive stroke of the table. A fluid pressure feeding or indexing mechanism is provided automatically to index or traverse the grinding wheel I2 transversely at either or both ends of the table stroke. As illustrated in the drawings, the cylinder is mounted within the vertically movable slide I4. A slidably mounted piston 66 within the cylinder 65 isconnected by a piston rod 61 to a bracket 68 which projects rearwardly from the wheel slide I3. A reversing valve 69 is provided to facilitate changing the direction of transverse movement of the wheel slide I 3. The valve 69 is of the balanced piston type, in which fluid conveyed from a source of fluid'pressure enters through a pipe .19, into a valve chamber IIJI between two valve pistons. As illustrated diagrammatically in Fig. 2, fluid under pressure passing through the pipe I0 and into the valve chamber IIJI passes through a passage I04 into a cylinder chamber I05 so as to cause a movement of the piston 66, the wheel slide I3 and the grinding wheel I2 toward the left (Fig. 2). During the movement of the piston 56 toward the left, fluid is exhausted from a cylinder chamber I06, through a passage IIJ'I, through a valve chamber I03 and a pipe I08, into the reservoir 25 within the base III of the machine.

The reversing valve 69 may be moved manually by means of a knob I8 mounted on the left-hand end of a valve stem 19; or, if desired, an automatically actuated reversing mechanism may be provided for shifting the reversing valve 69 when the wheel slide I3 has been moved through a predetermined distance in either direction. This mechanism may comprise a pair of adjustable dogs and 8| which are adjustably mounted on a bar or member 82 which is fixedly mounted on the wheel slide I 3. The dogs 80 and 8| are arranged to engage a lever 83 which is fixedly mounted on the lower end of a rock shaft 84. The rock shaft 84 carries an arm 85 at its upper end-having a roller 86 engaging a spring-pressed plunger 81. The upper end of the rock shaft 84 carries an arm 88 which is connected by a pin (not shown) which rides in a groove in the valve 69. It will be readily apparent from the foregoing disclosure that the wheel slide I3 moves toward the right, as viewed in Fig. 2'. The movement will continue until the dog 80 engages the arm 83 and rocks the roller 86 by the springpressed plunger 81, thereby shifting the reversing valve 69 into a reverse position to change the direction of transverse movement of the grinding wheel slide I3 and the grinding wheel I2.

The grinding wheel slide I3 may, if desired, be traversed transversely by means of a manually operable traversing mechanism comprising a hand wheel 90 which is operatively connected to rotate a gear 9| (Fig. 1). The gear 9| meshes with a rack bar 92 flxedly mounted on the upper surface of the wheel slide I3. This mechanism has not been shown or described in detail, since it is not considered to be a part of the present invention. For further details of construction, reference may be had to the prior U. S. patent to Flygare and Wood, No. 2,022,542, dated November 26, 1935, for details of disclosure not contained herein.

In order to obtain the maximum efficiency in a surface grinding operation, it is desirable to provide a transverse indexing or feeding mechanism whereby the-grinding wheel I2 may be indexed or traversed transversely by an amount equal to substantially the width of the wheel at each or both ends of the work table stroke so that the grinding Wheel I2 abrades a different path across the plane face of the work at each reciprocation of the work table II. In order to obtain a uniform transverse feeding movement, it is desirable to provide a mechanism whereby a positive fluid pressure is maintained on one side of the piston 66 to move the slide transversely at each reversal and to govern the extent of the transverse movement of the grinding wheel I2 by metering the exhaust of fluid from the wheel slide cylinder 65. Fluid'under pressure from the pump 21 passes through a pipe 95 to a speed control or throttle valve 96. In the positron of the valve 96 (Fig.2) unrestricted passage,

2 to allow unrestricted passage or fluid under pressure to the wheel-slide traverse cylinder 65 or, if desired, the valve 96 may be rotated .so that-a port 99 is more or less uncovered so that fluid under pressure may pass through a port I in the valve casing so that a slow continuous;

located at the right-ma inas: the We no. The admission of fluid underpressure to the valve chamber serves-to move the valve pistons I20 and .II9 toward the left-against the compression of a spring I32. The shifting of the valve pistons I20 and II9 toward the left serves to connect the'pipe I09 with the pipe III so'that/Z v fluid under pressure within the chamber I exerted on the piston 66 causes the piston to force fluid from the cylinder chamber I06, through the pipes previously described, into the valve H0, and through the pipe III into the I I metering valve chamber II2.

traversing movement of the wheel slide I3 may be obtained for a grinding wheel truingoperation.

The wheel slide reversing or control valve 69 is a piston type valve having a plurality of spaced valve pistons formed integrally therewith which form valvechambers IOI, I02 and I03. In the position of the valve 69 (Fig. 2), fluid under pressure from the pipe 91 and pipe" enters the valve chamber IN and passes through'a passage I04 into a cylinder chamber I05 to move'the piston 66 toward the left, thus moving the wheel slide I3 and the grinding wheel I2 toward the left, as governed by the exhaust of fluid from a cylinder chamber I06. Fluid in the cylinder chamber. I06 exhausts through a passage I0'I into the valve chamben I03 and passes out through a pipe I08 and a pipe I09 to a fluid pressure actuated valve IIO which is controlled in a manner to be hereinafter described. When the valve IIO is .opened, the fluid in the pipe I09 may exhaust through'a pipe III into a chamber II2 of a metering valve H3. The metering valve I I3 comprises a valve piston II4 which is normally urged in aright-hand' direction by a spring H6. An adjustable stop I I6 is provided on the end of a manually operable adjusting screw I I1 to-limit the movement of the metering'valve H3 in a The piston 66 can only move a distance as permittedby the amount of fluid which can be exhausted into the metering valve I I3. The'valve stem I26 is only held downwardly for an instant due to the swinging :of the roller I30. As the roller I30 rides over the top of the valve stem I26, the-released compression of the spring I29 moves the valve stem I26 up'w rdly into the position shown in Fig. 2 which erves to cut off fluid under pressure from the pipe I3I and connects the pipe I3I with a 'pipe I34. The pipe I34 connects with the exhaust pipe 40 so that fluid within the right-hand end chamber of the valve I-I0 may exhaust through the pipe I3I, the valve chamber located between the valve pistons I21 and I20, and out through the pipes I34 and 40 into the reservoir 25. As the released compression of the spring 32 shifts the valve pistons II9 and I29 toward the right (Fig. 2) the valve piston II9 cuts off further exhaust'from the pipe Y direction toward the ,left so as to limit the amount of fluid which may exhaust from the cyl- In order that the grinding wheel I2 may be indexed or traversed transversely at the ends ofthe work table stroke, a control valve I25 is provided which is actuated by and in timed relation with the table reversing mechanism. The valve I25 is a piston type valve comprising a valve stem I26 having formed integrally therewith valve "chambers I05 and I06, thus enabling the hand I09 and connects the metering valve chamber II2, through pipe III, the valve chamber H8, and the .pipe I2I, with the exhaust pipe 40 so that fluid within the metering valve chamber I I2 may exhaust into the reservoir 26 so that the metering valve is ready for the next wheel slide indexing or feeding movement; It will be readily apparent from the foregoing disclosure that each time the table reversing lever 45 is shifted by the table dogs 41 or 48, a measured quantity of fluid will be allowed to exhaust from the cylinder 65 so that pressure onthe active side of the piston 66 will traverse the wheel slide I3 and grinding wheel I2 by a precise and predetermined amount.

In case it is desired to traverse the wheel slide I3 manually, the reversing valve 69 may be shifted to a central or neutral position so that fluidmay readily by-pass between the cylinder traverse wheel 90 to be rotated without the necessity of overcoming the fluid pressure within the pistons I21 and I28. The valve is normally held in an upward position by means of a compresion spring I29. An actuating roller I30 mounted on the lever 55 is arranged to engage and depress the valve stem I26 each time the reversing lever 45 is shifted to reverse the table movement.

As shown in Fig. 2, fluid under pressure in the pipe 95 is cut off from the valve. I25 by the valve piston I2 When the lever 55 swings during reversal, he roller I30 pushes the valve stem I26 downwardly so that fluid under pressure fromthe pipe 95 enters a valve chamber located be tween the valve pistons I21 and I28 and passes out through a pipe I3I, into a valve chamber system.

During a grinding wheel truing operation, it is desirable to render the metering valve and associated mechanism inoperative so that it will not function each time the reversing lever is shifted either automatically or manually. To accomplish this desired result, a manually operable bypass valve I40 is provided. The valve J40 is a piston type.valve comprising a valve stem I4I having formed integrally therewith a plurality of valve pistons I42, I43 and I44. When it 'is desired to render the metering valve H3" and the valve I25 inoperative, a control knob I45, mounted on the valve stem MI, is moved toward the left (Fig. 2). Shifting the valve I40 into 4 its left-hand position serves to allow fluid under pressure in the pipe to pass through a valve chamber formed between the valve pistons I43 and I44 and to pass outwardly through a pipe I46 into a chamberI4'I at the upper end of the valve I25. .The admission of fluid under pressure to the chamber I41 moves the valve pistons I21 and I28 downwardly so that fluid within the pipe 95 enters a valve chamber located between the valve pistons I21 and I28 and passes out through the pipe. I3I into the cylinder chamber for the next actuation. 1 By turning the knob II1, the stop IIB may be adjusted to vary the at the right-hand end of the valve I I to move thus returning any exhaust fluid under pressure from the pipe I09 to the reservoir 25. It will be readily apparent from the foregoing disclosure that by operation of the by-pass valve I40, the valve I may be held in its downward position .20 that it is not actuated each time the reversing lever is shifted either automatically or manually. In the above-mentioned left-hand position of the by-pass valv"I40, the metering chamber I I2 together with the pipe III is also connected directly with the exhaust pipe 40, thus rendering the metering valve II3 inoperative while the valves are in the above-mentioned condition. 4

The operation of this improved machine will be readily apparent from the foregoing disclosure. A work piece to be ground is mounted on the upper surface of the table II and a readjusted to meter a desired and predetermined quantity of fluid from the cylinder 65 so that fluid .under pressure at one end of the' cylinder 65 will index or traverse the wheel slide I3 and the grinding wheel I2 transversely a precise and predetermined distance for the next pass of the work piece beneath the wheel I2; At each actuation of the table reversing lever 45 by means of th table dogs 41 and 48, the lever will swing the roller I30 into engagement with the valve stem I26 instantaneously to depress the valve pistons I27 and I28 to admit fluid under pressure to shift the valve 0 to its left-hand end position so that fluid from the cylinder may pass through pipev I09, the pipe III, into the metering valve chamber H2. The extent of movement of the wheel slide I3 and the extent of transverse movement of the grinding wheel I2 is governed by the adjusted capacity of the metering valve chamber I I2.

After the roller I30 passes over the valve stem I26, the released compression of the spring I29 shifts the valve stem I20 into its uppermost position, as shown in Fig. 2, which movement allows fluid from the metering valve chamber 2 to exhaust through the pipe III, through the valve chamber II8, through the pipe I2I and the pipe 43, i1rto the reservoir 25. The released comprescapacity of the metering valve chamber H2 and thereby to vary the extent of transverse indexing movement of the wheel slide I3 and the grinding wheel I2. I

It will be readily apparent that as the work piece mounted on the table II is reciprocated beneath the grinding wheel I2, the wheel I2 will index at each end of the table stroke in a manner hereinabove set forth until the grinding wheel I2 has ground the entire surface to be ground on the work piece. By means of the adjustable dogs and 8|, the reversing valve 69 is automatically shifted so that after the grinding wheel I2 has been indexed through a predetermined distance to grind the entire surface of the work piece, the valve 69 may be reversed so that the wheel I2 may be automatically indexed during a return transverse stroke thereof. It will be readily apparent that by providing a constant pressur within the active and of the cylinder 65 and metering a predetermined amount of fluid from the other end of the cylinder, a precise, uniform, and controlled predetermined indexing movement of the wheel slide I3 is obtained.

An adjustable throttle valve I50 is provided in the pipe I34 to facilitate a control of the valve H0 in its movement toward the right so as to prevent cutting off the passage of exhaust fluid to the metering valve chamber II2 until the chamber I I2 is filled.

It will thus be seen that there has been provided by this invention apparatus in which the successfully achieved. As many possible embodiments may be made of the above invention and III as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim;

1. In a surface grinding machine having a ba.s\, a work supporting table thereon, a rotatable grinding wheel, a wheel slide to support said wheel for a transverse movement relative to the :able, a vertically movable slide to support said wheel for movement toward and from the table, a fluid pressure system including a piston and cylinder operatively connected to reciprocate said table, a table actuated reversing-valve arranged to change the direction of movement of the table, 2. second piston and cylinder operatively connected to traverse said wheel slide, a second reversing valve which is arranged to convey fluid under pressure to one end or the other of said second cylinder, a metering valve to control the exhaust of fluid from said second cylinder, a normally closed valve which is opened automatically by and in timed relation with the shifting of the table reversing valve, and a pressure actuated stop and start) valve located between the normally c.0sed valve and the metering valve so that released pressure on said second piston forces a measured quantity of fluid from the other end of the wheel slide cylinder to produce a predetermined transverse movement of the grinding wheel at the end of the table stroke.

2. In a surface grinding machine as claimed in claim 1, the combination with the parts and features therein specified, of means including a table actuated reversing layer to actuate said reverstimed relation with the table reversing lever, and

amanualiy operable'by-pass valve to render said control valve and metering valve inoperative when desired. a

3. In a sur ace grinding machine having a base, a work sup orting table, thereon, a rotatable grinding wheel, a transversely movable wheel slide, a fluid pressure piston and cylinder operatively connected to reciprocate said table, a table actuated reversing valve arranged to change the direction of. movement of said table, a second piston and cylinder operatively connected to traverse the wheel slide, a wheel slide actuated reversing valve which is arranged to convey fluid under pressure to one end of the wheel slide cylinder, means including a fluid pressure pump to convey fluid under pressure through the wheel slide reversing valve to one end or the other of the wheel slide cylinder, means including a pipe to exhaust fluid from. the wheel slide cylinder, a metering valve in said pipe, a normally closed fluid actuated stop' and start valve to control the exhaust of fluid into the metering valve, and a valve actuated by-and in timed relation with the table reversing valve to control the opening of the stopand start valve during reversal so that released fluid under pressure in one end of said second cylinder moves said piston and exhausts a predetermined volume of fluid from the other end of the second cylinder as governed by said metering valve to cause a predetermined transverse movement of the grinding wheel slide at the end of the table stroke.

4. In a surface grinding machine having a base, a work supporting table thereon, a rotatable grinding wheel, a transversely movable wheel slide to support said wheel, a fluid pressure system including a piston and cylinder operatively connected to reciprocate said table, a table actuated reversing valve arranged to change the.direction of movement of the table, a piston and cylinder operatively connected to traverse said wheel slide transversely, a wheel slide actuated reversing valve which'is arranged to convey fluid under pressure to one end or the other of said wheel slide cylinder, a metering valve to control the exhaust of fluid from said cylinder, a normally-closed fluid-actuated stop and start valve to control the exhausting of fluid into the metering valve, a valve actuated by and in timed relation with they table reversing valve instantaneously to open the stop and start valve to admit exhausting fluid from the wheel slide cyl-- inder to the metering valve so as to facilitate a predetermined transverse movement of the wheel slide, and an adjustable throttle valve to regulate the rate of closing of said stop and start valve so as to insure a complete fllling oi the metering valve to provide a precise, predetermined transverse movement of the wheel slide at each table reversal.

HERBERT A. SILVEN. 

